1. Technical Field of the Invention
This invention relates to engine service monitoring systems. More particularly, this invention relates to a service monitoring system adapted for use with engines having at least a spark plug and an ignition circuit therefor.
2. Description of Related Art
Various service parameters are typically measured periodically with respect to the maintenance of a vehicle or its engine. For example, it is well-known in the motor vehicle art that engine durability is directly related to the lubricating ability of the engine crankcase oil, and that its lubricating ability degrades with engine operation and time. Accordingly, a service parameter relating to the operation of the engine is periodically monitored so that an indication that the oil needs to be replaced may be provided to an operator at appropriate times. It is also well-known that not only the engine oil's lubricating ability, but also a host of other engine and vehicular maintenance variables are typically related to the operation of the engine and elapsed time.
Therefore, it is widely recognized that various service intervals may be provided for the use of an operator of the vehicle or equipment so that recommended service maintenance schedules may be followed. By way example, automobile manufacturers of gasoline fueled passenger cars and light trucks typically recommend that, barring severe operating conditions, the engine oil should be changed every 7,500 miles (12,000 km) or 12 months, whichever comes first. Under severe operating conditions, however, the manufacturers' schedule recommends that the engine oil be changed every 3,000 miles (4,800 km) or 3 months, whichever comes first. In this regard, severe operating conditions are defined as including trips less than 4 miles (6.4 km) in below freezing weather, extended idling, trailer towing, operating in dusty areas, and extended stop-and-go driving.
With respect to the automobile engine oil example described above and in regard to the use of engine oil in engines for other equipment, several solutions currently exist for determining when it is required to change the oil in the engine. However, these solutions are typically beset with numerous shortcomings and deficiencies. For example, existing engine oil monitoring systems may be used only on an engine having a tachometric output on the primary side of the transformer used in the engine ignition circuit. Those of ordinary skill in the art should appreciate that such engines are typically found only in vehicles with distributors, thereby greatly limiting the types of engines with which the extant oil monitoring systems may be used.
Some current solutions require connections through the firewall that separates the engine compartment and the space occupied by human operators. Therefore, not only is the ease of installation of the current monitoring systems reduced thereby, but the operator safety is also compromised to a significant degree.
Moreover, conventional oil monitoring systems typically come with factory-loaded engine-type coefficients and service interval thresholds which cannot be altered or adjusted in the field. Accordingly, these systems are generally restricted to the factory-set engine types only. Additionally, known oil monitoring systems are not, in general, adaptable for use with different types of engine fuel. Also, they cannot adapt to different number of cylinders or the strokes/cycles of an engine. That is, a conventional engine monitoring system cannot typically be used accurately with an engine that can be operated with several fuels. Nor can a monitoring system, usable with a single cylinder engine, be used with an engine that has multiple cylinders. Similarly, a monitoring system usable with a two-stoke engine may not be usable with a four-stroke engine.
Accordingly, based upon the foregoing discussion, it should be readily appreciated that there exists an acute need for an engine service monitoring system that overcomes the deficiencies and shortcomings of the existing solutions described hereinabove. The present invention provides such an advantageous solution. It will be recognized upon reference hereto that although the teachings of the present invention are exemplified in terms of the engine oil change service parameter, various other service parameters may also be monitored within the scope hereof.